Re: Proposal for Allow postgresql.conf values to be changed via SQL

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Magnus Hagander <magnus@hagander.net>
Cc: Amit Kapila <amit.kapila@huawei.com>, Robert Haas <robertmhaas@gmail.com>, Josh Berkus <josh@agliodbs.com>, Christopher Browne <cbbrowne@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2012-11-07T17:29:03Z
Lists: pgsql-hackers
Magnus Hagander <magnus@hagander.net> writes:
> On Wed, Nov 7, 2012 at 6:19 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> You could dig it out of the stack if it's there, but that doesn't fix
>> the race-condition aspect.  Now a race is inevitable if two sessions try
>> to set the *same* variable, but I think people will be unhappy if a SET
>> on one variable makes a recent SET on some other variable disappear.

> I think if we require an exclusive lock on a single global lock for
> "set permanent", people are quite ok with that, really.

That doesn't fix it either, at least not without a whole lot of other
changes --- we don't normally read the config file within-commands,
and there are both semantic and implementation problems to overcome
if you want to do so.

			regards, tom lane